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Mix-up behind Aust soldier's grave error

Authorities in charge of Australian war graves in France are being urged to correct the gravestone of a soldier killed during the notorious WWI battle of Fromelles 100 years ago.

A clerical error made after the battle in July 1916 appears to have led to the wrong date of death being inscribed on the gravestone for Company Sergeant Major (CSM) Harold Woodman.

His remains were buried at the Fromelles (Pheasant Wood) Military Cemetery in 2010 after being unearthed from a nearby mass grave containing 250 Australian and British soldiers.

The battle of Fromelles lasted just 14 hours between July 19 and 20 and resulted in 5533 Australian casualties, including 1917 dead and 470 prisoners.

But CSM Woodman's gravestone says he died on July 21, a date experts insist is wrong and want changed before a major ceremony is held for the centenary of the battle - the deadliest in Australian military history.

The identities of 150 soldiers buried at the cemetery have been confirmed.

All except CSM Woodman have July 19 or 20 etched on their gravestones.

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Experts say a clerical error during a roll call on July 21 is likely to blame for the error on the gravestone erected for CSM Woodman after his remains were identified in 2014.

Lambis Englezos, whose years of research led to the mass grave being discovered, says up to five other soldiers have had their gravestones corrected and the same should be done for CSM Woodman.

"If we have the chance to correct the date, we should. Don't denigrate these men," Mr Englezos told AAP.

"And we should make a strong memo to ourselves that no more 21st of July is put on the gravestones of any soldiers identified at Fromelles in future."

Historian Neville Browning said each soldier recovered from the mass grave died behind German lines on July 19 or 20.

But a mix-up about the date CSM Woodman died was probably because his commanding officer with the 31st Battalion didn't submit an after-battle report until July 21.

"Anyone missing would have been named as missing on that date and then subsequently amended to say died that day," said Mr Browning, who authored the book Fromelles to Nauroy: 31st Battalion AIF 1915-1919.

Adding to the confusion are Red Cross records stating CSM Woodman was killed in action on July 21, but also that he "fell" near Fromelles on July 19.

The Office of Australian War Graves spokeswoman Valda Brewer said the matter was being investigated.

"Should the date be incorrect, the Commonwealth War Graves Commission will be advised and the headstone corrected in due course," she said.

A Commonwealth War Graves Commission spokesman said the headstone could be corrected in time for the centenary if requested.